Pyrido-imidazodiazepinones as a new class of reversible inhibitors of human kallikrein 7 (original) (raw)
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Kallikrein-related peptidase 6 (KLK6) is a secreted serine protease that belongs to the family of tissue kallikreins. Aberrant expression of KLK6 has been found in different cancers and neurodegenerative diseases, and KLK6 is currently studied as a potential target in these pathologies. We report a novel series of KLK6 inhibitors discovered in a high-throughput screen within the European Lead Factory program. Structure-guided design based on docking studies enabled rapid progression of a hit cluster to inhibitors with improved potency, selectivity and pharmacokinetic properties. In particular, inhibitors 32 and 34 have single digit nanomolar potency against KLK6, with over 25-fold and 100-fold selectivity, respectively, against the closely related enzyme trypsin. The most potent compound, 32, effectively reduces KLK6-dependent invasion of HCT116 cells. The high potency in combination with good solubility and low clearance of 32 make it a good chemical probe for KLK6 target validatio...
Natural and synthetic inhibitors of kallikrein-related peptidases (KLKs)
Biochimie, 2010
Including the true tissue kallikrein KLK1, kallikrein-related peptidases (KLKs) represent a family of fifteen mammalian serine proteases. While the physiological roles of several KLKs have been at least partially elucidated, their activation and regulation remain largely unclear. This obscurity may be related to the fact that a given KLK fulfills many different tasks in diverse fetal and adult tissues, and consequently, the timescale of some of their physiological actions varies significantly. To date, a variety of endogenous inhibitors that target distinct KLKs have been identified. Among them are the attenuating Zn 2þ ions, active site-directed proteinaceous inhibitors, such as serpins and the Kazal-type inhibitors, or the huge, unspecific compartment forming a 2 -macroglobulin. Failure of these inhibitory systems can lead to certain pathophysiological conditions. One of the most prominent examples is the Netherton syndrome, which is caused by dysfunctional domains of the Kazal-type inhibitor LEKTI-1 which fail to appropriately regulate KLKs in the skin. Small synthetic inhibitory compounds and natural polypeptidic exogenous inhibitors have been widely employed to characterize the activity and substrate specificity of KLKs and to further investigate their structures and biophysical properties. Overall, this knowledge leads not only to a better understanding of the physiological tasks of KLKs, but is also a strong fundament for the synthesis of small compound drugs and engineered biomolecules for pharmaceutical approaches. In several types of cancer, KLKs have been found to be overexpressed, which makes them clinically relevant biomarkers for prognosis and monitoring. Thus, down regulation of excessive KLK activity in cancer and in skin diseases by small inhibitor compounds may represent attractive therapeutical approaches.
Isomannide-Based Peptidomimetics as Inhibitors for Human Tissue Kallikreins 5 and 7
ACS Medicinal Chemistry Letters, 2014
Human kallikrein 5 (KLK5) and 7 (KLK7) are potential targets for the treatment of skin inflammation and cancer. Previously, we identified isomannide derivatives as potent and competitive KLK7 inhibitors. The introduction of N-protected amino acids into the isomannide-based scaffold was studied. Some KLK5 inhibitors with sub-micromolar affinity (K i values of 0.3-0.7 µM) were identified and they were 6-to 13-fold more potent than our previous hits. Enzyme kinetics studies and the determination of the mechanism of inhibition confirmed that the new isomannide-based derivatives are competitive inhibitors of both KLK5 and KLK7. Molecular docking and MD simulations of selected inhibitors into the KLK5 binding site provide insight into the molecular mechanism by which these compounds interact with the enzyme. The promising results obtained in this study opens new prospects on the design and synthesis of highly specific KLK5 and KLK7 inhibitors.
Chemistry & Biology, 2009
Human kallikrein-related peptidase 4 (hk4/prostase), a trypsin-like serine protease, is a potential target for prostate cancer treatment as a consequence of its proteolytic ability to activate many tumorigenic and metastatic pathways such as the protease activated receptors (PARs). Currently there are no KLK4specific small-molecule inhibitors available for therapeutic development. Here we re-engineer the naturally-occurring sunflower trypsin inhibitor (SFTI) to specifically block the proteolytic activity of KLK4 and prevent stimulation of PAR activity in cell based systems. The re-engineered inhibitor was designed using a combination of molecular modelling and sparse matrix substrate screening. The resulting inhibitor showed highly specific inhibition of KLK4 against the peptide substrate FVQR-para-nitroanilide (K i of 3.25 ± 1.60 nM) and the macromolecular substrate fibrinogen, blocked KLK4 initiated calcium flux from PAR2 and displayed remarkable stability in cell based assays with a half life of four days.
Inhibitors of kallikrein‐related peptidases: An overview
Medicinal Research Reviews, 2017
Kallikrein‐related peptidases (KLKs) are a family of 15 secreted serine proteases that are involved in various physiological processes. Their activities are subtly regulated by various endogenous inhibitors, ranging from metallic ions to macromolecular entities such as proteins. Furthermore, dysregulation of KLK activity has been linked to several pathologies, including cancer and skin and inflammatory diseases, explaining the numerous efforts to develop KLK‐specific pharmacological inhibitors as potential therapeutic agents. In this review, we focus on the huge repertoire of KLKs inhibitors reported to date with a special emphasis on the diversity of their molecular mechanisms of inhibition.
Isomannide derivatives as new class of inhibitors for human kallikrein 7
Bioorganic & Medicinal Chemistry Letters, 2012
Human kallikrein 7 (KLK7) is a potential target for the treatment of skin inflammation and cancer. Despite its potential, few KLK7-specific small-molecule inhibitors have been reported in the literature. As an extension of our program to design serine protease inhibitors, here we describe the in vitro assays and the investigation of the binding mechanism by molecular dynamics simulation of a novel class of pseudo-peptide inhibitors derived from isomannide. Of the inhibitors tested, two inhibited KLK7 with K i values in the low micromolar range (9g = 1.8 µM; 9j = 3.0 µM). Eadie-Hofstee and Dixon plots were used to evaluate the competitive mechanism of inhibition for the molecules. Calculated binding free energies using molecular MM/PB(GB)SA approach are in good agreement with experimental results, suggesting that the inhibitors share the same binding mode, which is stabilized by hydrophobic interactions and by a conserved network of hydrogen bonds.
Natural and engineered kallikrein inhibitors: an emerging pharmacopoeia
Biological Chemistry, 2000
The kallikreins and kallikrein-related peptidases are serine proteases which control a plethora of developmental and homeostatic phenomena ranging from semen liquefaction to skin desquamation and blood pressure. The diversity of roles played by kallikreins has stimulated considerable interest in these enzymes from the perspective of diagnostics and drug design.
The serine protease kallikrein-related peptidase 7 (KLK7) is a member of the human tissue kallikreins. Its dysregulation leads to pathophysiological inflammatory processes in the skin. Furthermore, it plays a role in several types of cancer. For the treatment of KLK7-associated diseases, coumarinic esters have been developed as small molecule enzyme inhibitors. To characterize the inhibition mode of these inhibitors, we analyzed structures of the inhibited protease by X-ray crystallography. Electron density shows the inhibitors covalently attached to His57 of the catalytic triad. This confirms the irreversible character of the inhibition process. Upon inhibitor binding His57 undergoes an outward rotation thus the catalytic triad of the protease is disrupted. Besides, the halophenyl moiety of the inhibitor was absent in the final enzyme-inhibitor complex due to hydrolysis of the ester linkage. With these results, we analyze the structural basis of KLK7 inhibition by covalent attachment of aromatic coumarinic esters.
Biological chemistry, 2018
The activity of kallikrein-related peptidase 6 (KLK6) is deregulated in various diseases such as cancer and neurodegenerative diseases. KLK6 is thus considered as an attractive therapeutical target. In this short report, we depict some novel findings on the regulation of the KLK6 activity. Namely, we identified mechanism-based inhibitors (suicide substrates) from an in-house library of 6-substituted coumarin-3-carboxylate derivatives. In addition, a molecular dynamics study evidenced the allosteric behavior of KLK6 similar to that previously observed for some trypsin-like serine proteases. This allosteric behavior together with the coumarinic scaffold bring new opportunities for the design of KLK6 potent activity modulators, useful as therapeutics or activity-based probes.